This invention relates to polymers.
More specifically, this invention relates to acrylateacetoacetate copolymers and to coatings or films produced from these copolymers.
In one of its more specific aspects, this invention pertains to cross-linked copolymers which are the reaction products of polyfunctional acrylates and diacetoacetates.
The resilient flooring industry is continually searching for new abrasion-resistant polymeric compositions which will serve as wear layers for decorative surface coverings, especially thermoplastic floor coverings.
The present invention provides novel acrylate-acetoacetate polymers which exhibit excellent film-forming properties and abrasion-resistant properties. Accordingly, these polymers, in film form, are well suited for use as wear layers for decorative thermoplastic floor coverings.
According to this invention, there is provided a crosslinked acrylate-acetoacetate polymer produced by the reaction of at least one polyfunctional acrylate with at least one diacetoacetate in the presence of a catalyst capable of promoting the reaction between the polyfunctional acrylate and the diacetoacetate.
Also, according to this invention, there is provided a thermoplastic floor covering coated with a wear layer composition comprising a cross-linked acrylate-acetoacetate polymer produced by the reaction of at least one polyfunctional acrylate with at least one diacetoacetate in the presence of a catalyst capable of promoting the reaction between the polyfunctional acrylate and the diacetoacetate.
As the polyfunctional acrylate, use can be made of compounds having the formulae EQU R--O--C(O)--CH.dbd.CH.sub.2).sub.4, EQU R.sup.1 --O--C(O)--CH.dbd.CH.sub.2).sub.3, or EQU R.sup.2 --O--C(O)--CH.dbd.CH.sub.2).sub.2
wherein R represents ##STR1## R.sup.1 represents ##STR2## R.sup.2 represents: a (C.sub.1 to C.sub.10) alkylene group, a (C.sub.1 to C.sub.4) alkyl substituted (C.sub.1 to C.sub.10) alkylene group, ##STR3## a cycloalkylene group, a cycloalkane bearing two (C.sub.1 to C.sub.3) alkylene groups, ##STR4## R.sup.3 represents hydrogen or (C.sub.1 to C.sub.3) alkyl; a is an integer from 1 to 20; b is an integer from 1 to 10; and c is an integer from 1 to 5.
Representative of the above useable polyfunctional acrylates are trimethylol propane triacrylate, pentaerythritol tetraacrylate, hexanediol diacrylate, polyethylene glycol (200) diacrylate, ethylene glycol diacrylate, tripropyleneglycol diacrylate, trimethyl hexane diol diacrylate, 1,4-cyclohexanedimethanol diacrylate, dibutylene glycol diacrylate, 1,4-cyclohexane diacrylate, dipropyleneglycol di-2-acrylyl-ethyl ether, methylenebis(4-cyclohexane-2-acrylyl-ethyl urethane), 2,2,4-trimethylhexanebis(2-acrylyl-ethyl urethane), isophorone di(2-acrylyl-ethyl urethane), and the like.
The three above-recited urethane-containing diacrylates are not known to be commercially available. Accordingly, Examples III through V demonstrate the preparation of each urethane-containing diacrylate recited above.
As the diacetoacetate, use can be made of compounds having the formula EQU R.sup.4 --O--C(O)--CH.sub.2 --C(O)--CH.sub.3).sub.2
wherein R.sup.4 represents: a (C.sub.1 to C.sub.10) alkylene group, a (C.sub.1 to C.sub.4) alkyl substituted (C.sub.1 to C.sub.10) alkylene group, ##STR5## a cycloalkylene group, a cycloalkane bearing two (C.sub.1 to C.sub.3) alkylene groups, and --H.sub.6 C.sub.3 O--C.sub.2 H.sub.4 O--.sub.f --C.sub.2 H.sub.4 --OC.sub.3 H.sub.6 --, d is an integer from 1 to 6; e is an integer from 1 to 6; and f is an integer from 1 to 4.
Representative of the above usable diacetoacetates are diethylene glycol di-3-acetoacetate propyl ether, hexanediol-diacetoacetate, 1,4 cyclohexanebis(methylacetoacetate), 1,3 cyclohexanebis (methylacetoacetate), 2,2,4-trimethylhexamethylenediacetoacetate, 1,3-propanediacetoacetate, diethyleneglycol-di-2-acetoacetate-ethyl ether, dipropyleneglycol diacetoacetate propyl ether, 1,4-cyclohexanebis (acetoacetate), trimethylhexamethylene diacetoacetate, and the like.
The diacetoacetates are not known to be commercially available. Accordingly, Examples 1 and 2 below demonstrate methods for preparing diacetoacetates suitable for use in this invention.
The amounts of polyfunctional acrylate and diacetoacetate can be varied within relatively wide ranges. Preferably, about 1 to about 2 moles of diacrylate, about 2/3 mole to about 11/3 moles of triacrylate or about 1/2 mole to about 1 mole of tetroacrylate are employed for every mole of diacetoacetate. Best results are usually obtained when the polyfunctional acrylate (based on diacrylate) is reacted with the diacetoacetate in a mole ratio of from about 1.2 to about 1.4 moles of diacrylate to about 1 mole of diacetoacetate.
As the catalyst to promote the reaction, a Michael reaction, use can be made of any of a variety of well known Michael reaction-type catalysts commonly employed to promote condensation. Particularly suitable are strong basic catalysts such as sodium methoxide, sodium metal, sodium ethylate, benzyl-trimethyl ammonium methoxide, and the like. Catalytic amounts of materials are selected in accordance with well known practices in the polymer art, the amount being one sufficient to promote the polycondensation reaction. For further information relating to the Michael reaction mechanism, see "The Michael Reaction" by E. D. Bergmann et al., Organic Reactions, Vol. 10, chapter 3, pages 179-555, and Modern Synthetic Reactions, H. O. House, 2nd Ed. (1972), pages 595-623, both herein incorporated by reference.
The polymerization reaction can be carried out using the reactants as the only reaction medium since both the polyfunctional acrylates and the diacetoacetates are normally in the liquid state and/or they can be uniformly blended together.
In one embodiment of this invention, if the acrylate-acetoacetate polymer is employed to produce a wear layer composition, the polymerization reaction can be carried out in the presence of art recognized amounts of optional ingredients typically employed in wear layer compositions such as surfactants, heat and light stabilizers, and the like.
The following examples will serve to more fully illustrate specific embodiments of and the best mode for practicing this invention.